Caliper using differential series of gauge blocks



July 14, 1953 N. TRBOJEVICH 3 CALIPER USING DIFFERENTIAL SERIES OF GAUGE BLOCKS Filed Nov. 1, 1947 2 Sheets-Sheet l Faced,

' 25 FlGAa- FlG .4b.

IN V EN TOR.

July 14, 1953 N. TRBOJEVICH CALIPER USING DIFFERENTIAL SERIES OF GAUGE BLOCKS 2 Sheets-Sheet 2 Filed Nov. 1, 1947 FIG.6.

FRACTIONS I l- .aool] Ls-.3oa|

\INTEGERS ,2? I [A- 300 1 L2- .3003] [ts-.3243 [a- .900 1 I 3- 500?] Lr-.3729 (I- 2.7001

D A A D B O O 8 CODE FRACTION x" F I G 8 INVENTOR.

FlG.7.

Patented July 14, 1953 GALIPER USING DIFFERENTIAL SERIES OF 1 GAUGE BLOCKS Nikola Trbojevich, Detroit, Mich. Application November 1, 1947, Serial No. 783,482 s Claims. (01, 33-168) The invention relates to an improvement in precision gauges and calipers.

In particular, this application may be considered as a continuation-in-part of my two prior and copending applications, viz: Serial No. 545,990, filed June 21, 1944 Gauges, abandoned February 27, 1950, and Serial No. 579,789, filed February 26, 1945, Angle Measuring Bar and Gauges, now Patent No. 2,446,562, issued August 10, 1948. A reference is further being made to a third copending application, Serial No. 725,999, filed February 3, 1947, Precision Weights and Balance, abandoned January 12, 1952, in which certain mathematical deductions pertaining to this novel system of differential measurement are found. r

The object is to construct a caliper-like measururing tool capable of measuring both male and female distances, i. e. externally and internally with an extreme accuracy.

Another object is to construct a tool of the indicated type in the form of an assembly of interchangeable measuring blocks of the adhering or Swedish type. p

A further object is to obtain numerouscombinations by using only relatively few measuring blocks. v

Another object is to construct a caliper of the indicated type in which the gauge blocks are enclosed at all sides and protected from damage by means of replaceable auxiliary members.

A further object is to employ two L-shaped projecting plates or jaws of such a form that they may be used either for male or female measurement by means of a simple transposition and are further capable of nesting in each other whereby small male and female distances may be measured.

Still another object is to employ measuring and auxiliary blocks of a much heavier cross section than was formerly possible without sacrificing the lower ranges of measurement thereby,

Another object is to furnish a set of measurin blocks which may be used for various purposes in a differential manner, e. g. in connection with sine or angle rectifying bars according to the teachings of my application, Serial No. 579,789.

A further object is to reduce the cost and increase the accuracy of precision distance measurement.

These and other objects will now be more fully explained.

In the drawings:

Figure 1 shows the new caliper adapted to take a male orexternal type of measurement,,inelevation and perspective;

Figures 2a and 2b are two views of the L block used in this appliance;

Figures 3a and 3b are two views of the measuring block; 7

Figures 4a and'4b are two views of the end plate I2; l u

Figure 5 is a modification of Figure 1 in which the L-shaped members are rearranged to form a female or internal type of measurement;

Figure 6 is a diagram showing a set of twelve measuring blocks;

Figures 7 and 8- are fragmentary views of two pages of the book of instruction and explanatory of the method of forming block combinations.

As shown in Figure 1, the new caliper is an assembly formed from a plurality of parallelepipedal measuring blocks II stacked in two columns of unequal heights at and 11 respectively, side byside beneath a top plate I2 andcovered at their lowermost faces by means of two L-shaped projecting pieces I3. The arrangement of the said projecting pieces I3 is such that their short shanks I! face each other in a'sub'stantial registry over the entire width of the device.

The contacting planes in the said parts are all strictly parallel andfinished to such an extent that they will adhereto each and form a solid prismatic body in the manner of the well known Swedish blocks when rubbed together. The screws I4 and the nuts I5 are furnished merely as a protective device against the accidental falling apart of the component pieces but they do not take part in or affect the accuracy of th measurement. Y

. In Figures 2a and 2b theformation of the L- shaped projecting block is shown. The long shank I6 is of a preselected width a and length 0 corresponding to the similar dimensions found in the gauge block I I The thickness b is exact and corresponds to the thickness of the unit measuring block. The short shank I! extends at right angles from the said shank I6 integrally therewith and its length is selected as twice the width of the said first shank. Its thickness 6 is less than the said thickness 1), whereby when two such blocks are brought in a juxtaposite position to form an" external type of measuring tool as in Figure 1, they are capable of nesting in each other whereby the minimum distance which can be measured is materially'reduced, or, conversely, whereby the thickness 5 may be increased without the disadvantage of increasing the minimum measurable distance, which is a distinct advantage inherent in this system. p

In the'midpoint of the said shank IS a hole I8 is formed, the said hole being provided at its length and a width a as already mentioned,

while its thickness H determined by the two strictly parallel measuring planes 2-3- and 24 respectively is variable and its exact numerical values for each block may be found in Figure 6. The said block is further providedwith. a centrally located hole I8 as shown.

In Figures 4a and 4b. the top plate I2 is shown in two projections. The saidplate istwice as wide as the aforementioned shank I6 and the block II and is provided with two holes I8.. as shown. Only one measuring plane 25 (the side which contacts the blocks I I in Figures 1 and needs to be finished. Its thickness may be selected within reasonable limits, at will.

Figure 5 is a diagram similar to Figure 1. in all respects except that the two L-shaped pieces I3 are turned around to faceeach other with their long measuring planes 22 and thereby furnish an exact. measurement between the said two planes. Incontra-distinctiontherewith, Figure 1 shows an arrangement in which the said measuring planes 22 are. turned away from each other, i. e. they are facing, outwardly corresponding to the opposite type of measurement. It follows from. inspecting the saidtwo. arrangements andby denoting withh' the external. and with h" the internal type. distance to be constructed that:

The minimum distances which can beconstructed h'mm and h min, external and internal,

are:

hmin: 2e (4) h"mm=o (5) The nuts. I5, Figure 1, are provided with knurlings 26 at their outer circumferences. to indicate that only finger pressure and not, perhaps a wrench should be used in. tightening the same. The screws I4 are furnished with each set in various-lengths and in sufficient numbers corresponding to the range of the caliper.

In. Figure 6 a box 27 containing twelve measuring blocks I I forming a typical set is diagrammatically shown. The said blocks form two. series, viz: an integral series comprising four blocks and a fraction. series comprising eight blocks. The integral blocks are numbered. with capital letters A to, D inclusive, while the fractions are. numbered witharabics I to 8 inclusive. The. thickness H in inches, whichis different for each block, also may be. stamped in as shown. A set of this kind for e=.100", see Figure 2b, is capable of furnishing all combinations in .0001" steps from .200" to 12" in external and. from 0 to 12" in internal types of measuring distances. The a: and 1/ block combinations for any partioular measurement are either determined mathematically by the operator or, more conveniently, are obtained from the book of instruction furnished with the set. The blocks shown in Figure 6 may also be used for measuring angles in connection with a sine bar or a radian bar as was explained in the mentioned application, Serial No. 579,789.

In Figures '7 and 8 two pages of the said book of instruction. are fragmentarily shown. Figure 7 relates to the fraction blocks I to 8 inclusive and Figure 8 relates to the integral blocks A to D inclusive. The integral series can be extended outwardly without aifecting the fractional series at will and, in such a case, each additional block multiplies the previous maximum range and the number of combinations by three.

The. mathematical procedure of determining the block thicknesses H and of computing the combinations as and y, Figures '7 and 8, will now bebriefly explained,

It is. believed that. the inventor was the first to. initiate an. accurate method of measuring angles, distances and weights by means of a specific differential system. In angle measurement, see Patent No. 2,134,062. of October 25, 1938, the blocks were arranged in a single geometrical series having only one constant. However, for the measurement of Weights and distances, the one-constant scheme would not work for the simple reason that while it is possible to construct. an. angle block. having an angle of, say, one second, one cannot make a measuring block .0601 thick or a weight equal. to a small iractionoi a milligram. Hence, I'conceived the idea of forming the blocks in two series based upon two constants in such a manner that the firstor the integral series is a simple geometric series, whilethe second series is a compound one comprising both constants. By this means it is now possible to compose the fractional part of a desired distance. or. number by means of the second or compound. series and then apply a correction in the first series by means of the integral elements contained in the second series. This is the basis of my invention. By this means the number, of blocks required to cover a given range is enormously reduced (from former 82 blocks down to 12), the blocks may be made thicker, stronger, and therefore more accurate than prior to this invention and very small distances, especially in. the internal type modification, Figure 5, may be accurately measured.

Another advantage of employing two series and two constants in the construction of a set of measuring blocks is that each distance may be constructed. in two fundamentally different block combinations, 1. e. a direct and a complementary combination. One usually chooses to use the simpler one of. the two, but, in some instances, one may use both combinations, one after the other,,for the purpose of checking the accuracy of the gauges.

In iorming the. said. two series, I first form the integral series S:

in.which,.for b=.300 theseries becomes in inches:

The compound or fraction series S." is next formed on the basis of the said constant b and 5.. another constant k which correspondsto'the unit spacing, in this case 70:.0001. Thuszw The number of blocks in the lastseries is'such that the sum of the fractional; members i e.

the memberscontaining-the factor k i's equalto or greater than the constant. b." Forieight blocks, the said sum is equal to-r328 whichiss greater than b='=;-.300-'andtherefore;satisfactory.

The method of forming any desired blockcom is important. I term the first constanta as the code number, se'eFigures .7 and8; In

Figure 7, the code number in: the first or direct row of combinations is equal to thedifiere'n'ce in digits in the columns as" and y" respectively. In the second or complementary line of combinations, the code number is equal .to the momentary digit difference less one. culiarity will be further explained;

The correction in the integral series for the This peexcess or deficiency in length of'the partial columns :v-y" is now accomplishable because the correction is always an integral multiple of the first constant b. Thus,the corrected integral partial combination,'denoted with the symbols :c-y' will be of the general form:

x'-y' bQED (12) in which both '7 and a are integers and their difference'is also an integer. q l

The Equations 1,' 2 and 3 show that the total combination xy difiers from the distances h and h to be measured due. to the effect of the thicknessb of the L block.--, .Thevalue-of the total combination a"-.y'for external oriinternal distances h and h" is therefore first determined from the Equation 3 which shows that forlthe first distancethe value of b must be subtracted from and for the second, added to the nominal distance. In other words, a certain block combination zr-y. having the numerical value 0f;';-?say, 5 inches will measure after the addition of the L I Thus, the complementary code number mustbe made by one smaller than it would"be"'-in "asimilar primary or direct combination. E. g. in Figure 7, let the fraction to be studied be .1632

The primary combination is"('2, 3, 6, 87 (5)?) The code number is equal to 2,,i, e. the difference in the numberof digitsin thefirst and second columns, 1:" andyv'. The complementary com-L bination corresponding to the same fraction, is

equal to: (a, 5,7) ,(s-) The digit diifere'nceis equal to 2, but in view of the Equation 16, the

correct code number is equal .to 21=1. The method of calculating the block c retically, any combination based on the progressive powers of three maybe found by calculation. It can be shown that any and all such combinations exist in the range extending from 1 to the sum of the series. I discovered that if the combinations are written down seriatim from 1 to 3000, corresponding. to the fraction series Figure 7, a certain regularity in the appearance and disappearance of various block numbers is observable resulting in the fact that the combinations may all be written down by a certain mentioned application, Serial No. 725,999 and will not be repeated here further for laokof,

space. v

The integral table, Figure 8,

consecutive lines. are, greaterand the number of I repetitions of the first ,or 0 column, downwardly I now form another combination of the form shifted one. line for each consecutive code numw ber. -1-

Hence, the I procedure of finding anthem; bination consists of finding the two partial-com binations inFigures'l and Band in adding them together. i i I I g table forms the connecting link between the said two tables. Obviously, a singletable could be constructed to cover all] the combinations, but,

it is believed that such a large book would be illustrating the method of calculating the block combinations for any given distance, internal or external.

ExampZe.-Find the :c'-y blocks, Figure 5, to

furnish h:7.9632, internal measure. From the Q said figure, I copy:

7.9632=a:'-y-.300 (17) xy:8.2632 (18) The combination for the decimal fraction .1632

is first found in Figure 7, last line:

' Code number one.

"mti F nations 2:" and y", Figure'l, and, 'xLy' binations, Figure 8, will now be discussed. 'I'ho-' is bi I simpler'construction than the said fractionaL table, Figure 7 in that the steps between the.

The code number-found in the,

Under this code number 7 and the integer 8,100 in Figure 8.. I find that the combination is:

a:'--y: (D), (A) (21.)

Hence, the total combination is :cy:(3, 5, '1', D)-(8, A) QED (22) and. the, caliper is readily assembled according to the, plan shown in Figure 5.

To illustrate the correctness of the above solution, I shall check over the last equation from the data found in Figure 6. Ordinarily, such a check should not be necessary in practical work because the tables are supposed to be free from errors.

What I claim. as my invention is:

1. A measuring device comprising a top plate, two L-shaped projecting members, a set of gauge blocks not exceeding twelve pieces and means for fastening two preselected blockstacks side by side upon the said plate and members, in which the thicknesses of the said blocks form two serie of the b and b+7c type, in which 12 in the first series and k in the second series form respective geometrical progressions, in which the thickness ofthe L membersis exactly equal to b and the short legs of, the said members protrude one above the other whereby both inside and outside measurements may be taken by the same device.

2. A device as described in claim 1 inwhich the blocks and L members are provided with one hole each, the, plate with two holes, in which the fastening means are two screws and nuts, in which the blocks are parallelepipedal and the short legs ofthe said L members overlap the said stacks, the plate and each other.

3. A device as described in claim 1 in whichthe geometric progressions correspond to successive integral, powers of three.

4. A. device asdescribed in claim 1 in which the sum or the b series corresponds to the range ofthe instrument and, the sum of the k members in the b+k series is greater than 5. A device as described in claim 1 in which the blocks are oblong parallelepipeds having lengths substantially greater than twice their widths, in which the plate is of the same length as the blocks and twice as wide as the said blocks, whereby a compact and easily portable instrument is obtained.

6. A device as described in claim 1 in which the short legs or the L members are gouged out and reduced in thickness for the purpose of enabling the said members to nest in each other when constructing. small distances of the external type.

'7. A device as described in claim 1 in which the blocks of the b. series are numbered with capital letters and those of the b+k series with arabic numerals whereby the construction of the combination tables is simplified and the operatormay construct various internal or external caliper settings without the knowledge of the exact block thicknesses.

8. A device as described in claim 1 in which the two block stacks are tightened by means 0! screws and in which the minimum block thickness b exceeds one-quarter inch for the purpose ofpreventing any measurable bending of blocks when the screws are tightened. by means of finger pressure.

NIKOLA 'I'RBOJEVICH.

References Cited in the file of this. patent UNITED STATES PATENTS Number Name Date 1,491,100 Hoke Apr. 22, 1924 2,134,062 'Irbojevich Oct. 25, 1938 2,446,562 Trbojevich Aug. 10, 1948 FOREIGN PATENTS Number Country Date 116,900 Australia Apr. 27, 1943 119,541 Great Britain Oct. 7, 1918 383,965 Germany Oct. 20., 1923. 559,748 Great Britain Mar. 3, 1944 OTHER REFERENCES Johansson Gage Block, Catalog, pp. 24-30 (1938). 

